scholarly journals Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment

2014 ◽  
Vol 54 (2) ◽  
pp. 125 ◽  
Author(s):  
J. C. Greeff ◽  
L. J. E. Karlsson ◽  
A. C. Schlink
Keyword(s):  
Genetic Correlations ◽  
Production Traits ◽  
Production Environment ◽  
Mediterranean Environment ◽  
Important Indicator ◽  
Body Conformation ◽  
Heritable Trait ◽  
Potential Indicator ◽  
Normal Production ◽  
Indicator Traits

Data from 2833 unmulesed Merino lambs from 49 sires and 1535 dams that were born from 2005 to 2009, were used to identify indicator traits for breech strike in a Mediterranean environment. Sheep were managed in a normal production environment where no preventative treatments were applied to protect them from being struck by flies, but were immediately treated when found to be fly struck. Seventy-seven skin, body conformation, wool, disease and production traits that may contribute to breech strike and that could qualify as potential indicator traits were recorded on progeny at birth, weaning, post-weaning, yearling, spring and at pre- and post-hogget age at ~18 months of age. In all, 31% of ewes and 22% of rams were fly struck in the breech area between birth and hogget shearing. The heritability of and the phenotypic and genetic correlations between the potential indicator traits and breech strike were estimated. The results showed that breech strike is a heritable trait (h2 = 0.51 ± 0.10), and that the most important indicator traits for breech strike were dags, scored at any time, especially at hogget age (rg = 0.81 ± 0.15), spring (rg = 0.77 ± 0.13) or at weaning (rg = 0.64 ± 0.00), urine stain scored at weaning (rg = 0.54 ± 0.13) and marking (rg = 0.51 ± 0.15), neck wrinkle at hogget age (rg = 0.46 ± 0.13) and breech cover (rg = 0.32 ± 0.15) scored at post-weaning shearing. These traits could be used to select indirectly for breech strike resistance in a Mediterranean environment.

Factors explaining the incidence of breech strike in a Mediterranean environment in unmulesed and uncrutched Merino sheep

2018 ◽  
Vol 58 (7) ◽  
pp. 1279 ◽  
Author(s):  
J. C. Greeff ◽  
L. J. E. Karlsson ◽  
A. C. Schlink ◽  
A. R. Gilmour
Keyword(s):  
Small Proportion ◽  
Significant Interaction ◽  
Consistent Pattern ◽  
Production Traits ◽  
Mediterranean Environment ◽  
Important Indicator ◽  
Merino Sheep ◽  
Potential Indicator ◽  
Indicator Traits ◽  
Indicator Trait

Factors responsible for an increase in breech strike were investigated in an unmulesed Merino flock in a Mediterranean environment that were not crutched in 4 years but were crutched in the subsequent 2 years. No chemical preventative treatments such as dipping or jetting were applied in order to assess the susceptibility of the different progeny groups. The number of breech strikes for each animal was recorded from birth to hogget shearing at 17 months of age. Production traits were measured and a large number of visual wool and body conformational traits were subjectively scored to determine whether they contribute to variation in breech strike. Large differences (P < 0.01) in the incidence of breech strike were found between years. A significant interaction (P < 0.05) was found between year of birth and sex for breech strike to weaning, as rams had a higher strike rate than ewes in 1 year only. Across years ewes generally had a higher strike rate than rams. No consistent pattern in potential indicator traits could be found across years, as many traits each explain a small proportion of the variation in breech strike. Dags and skin wrinkle in the tail and breech area contributed most to the variation in breech strike. In uncrutched sheep, dags scored at yearling age for rams, and before hogget shearing for ewes, explained 16% and 10% of the variation in breech strike, respectively, whereas tail wrinkle scored post-weaner shearing explained 21% of the variation in breech strike in both ewes and rams. In sheep that were crutched at yearling age, about 4 months before the normal fly season, tail wrinkle was the most important indicator trait of breech strike in rams, whereas dags at yearling and dags before hogget shearing were the most important indicator traits in ewes. This research confirms that dags and wrinkles are major predisposing factors to breech strike in a Mediterranean environment and that sheep with higher dag and wrinkle scores were consistently more likely to be struck. A large proportion of variation in the incidence of breech strike remains unexplained in uncrutched and unmulesed sheep.

scholarly journals 296 Awardee Talk: The Genetics of Sow Longevity

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 28-28
Author(s):  
Kenneth J Stalder
Keyword(s):  
Genomic Selection ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Parameter Estimate ◽  
Production Traits ◽  
Sow Longevity ◽  
Future Technologies ◽  
Indicator Traits ◽  
Additive Genetic Effects ◽  
The Impact

Abstract Sow longevity is a key productivity indicator trait that has real economic and welfare importance for commercial swine farms globally. The average parity at culling is 3.8 parities. Reports indicate that it takes 3 to 4 parities before a sow “pays for herself.” Research groups around the world have reported heritabilities estimates for sow longevity traits ranging from 0.05 to 0.35. Estimate differences result from the animal population under evaluation, the trait being evaluated, and the methodology employed to obtain the genetic parameter estimate. Because sow longevity is measured at the end of the sow’s productive life, indicator traits like age at first farrowing, leg conformation, and other traits are utilized in gilt selection programs. The genetic correlations between sow longevity and lifetime production traits range have been reported to range from 0.64 to 0.94, suggesting that selection will improve sow longevity. Genetic markers have been identified that affect both sow longevity and other indicator traits. Selection to improved sow longevity still requires phenotypes. Future technologies, e.g. CT scans, digital images, and automated disease detection, will provide additional phenotypes. Continued hardware, software, and molecular developments will improve selection accuracy for sow longevity traits and related traits. Research is needed to evaluate the impact that non-additive genetic effects have on sow longevity and other fitness-related traits. Sow longevity seems to be an ideal trait to employ genomic selection in order to make more rapid trait improvements because it is measured late in life, it is sex-limited, and the trait is not directly measured on nucleus animals. In conclusion, sow longevity and related traits have sufficient heritability and variation to improve through traditional and genomic enhanced selection methods. Selection programs employing effective genomic selection programs will be more effective in improving sow longevity trait and related traits and ultimately economical return.

scholarly journals Body weight, sexual maturity, and spinal deformity in strains and families of Atlantic cod (Gadus morhua) at two years of age at different locations along the Norwegian coast

2006 ◽  
Vol 63 (2) ◽  
pp. 246-252 ◽  
Author(s):  
K. Kolstad ◽  
I. Thorland ◽  
T. Refstie ◽  
B. Gjerde
Keyword(s):  
Body Weight ◽  
Spinal Deformity ◽  
Sexual Maturity ◽  
Atlantic Cod ◽  
Selection Index ◽  
Genetic Correlations ◽  
Production Traits ◽  
Production Environment ◽  
Arctic Cod ◽  
Norwegian Coast

Abstract Body weight, occurrence of spinal deformity, and sexual maturity were recorded in 51 full-sib families of the strains coastal and Arctic cod at two years of age. The family groups were located at three sites along the Norwegian coast including Hordaland, Møre and Romsdal (M&R), and Nordland County to detect genetic variation in important production traits and to investigate interactions between genetic composition and production environment. Body weight varied among locations partly owing to different production conditions. There were also large differences among the locations with respect to spinal deformity. M&R had the highest occurrence of spinal deformity (p < 0.001). Comparison of sexual maturity among the locations was made difficult owing to the different ways the trait was recorded. Only small differences were found between coastal and Arctic cod in spinal deformity (p < 0.05 in Hordaland) and sexual maturity (p = 0.06 in M&R), while no differences were found for body weight. Heritability estimates for body weight (0.51), spinal deformity (0.27), and sexual maturity (0.21) indicate the potential for improvement of all three traits by selective breeding using a family-based selection programme. Final recordings at the end of the growing period will provide further information. Genetic correlations estimated between weight and occurrence of spinal deformity (rg = 0.50) suggest that caution be used when selecting for growth, and that a need exists for including spinal deformity in the selection index. No significant correlations were found between these two traits and the incidence of sexual maturity.

scholarly journals Within- and across-flock genetic relationships for breech flystrike resistance indicator traits

2010 ◽  
Vol 50 (12) ◽  
pp. 1060 ◽  
Author(s):  
D. J. Brown ◽  
A. A. Swan ◽  
J. S. Gill
Keyword(s):  
Genetic Relationships ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
The Body ◽  
Production Traits ◽  
Sheep Industry ◽  
Selection Strategies ◽  
Australian Sheep ◽  
Fleece Weight ◽  
Indicator Traits

Flystrike is a major cost for the Australian sheep industry. The industry is currently implementing selection strategies for flystrike resistance to reduce the need for breech flystrike prevention. The following indicator traits are used to select for breech flystrike resistance: wool cover, skin wrinkle on the body and breech, scouring (dags) and wool colour. The aims of this study were to estimate genetic correlations between these indicator traits and production traits using the Sheep Genetics database, to distinguish between within- and across-flock genetic relationships, and to quantify responses to selection using indexes that include breech wrinkle as a proxy trait for flystrike resistance. Breech flystrike indicator traits are all heritable; however, there are significant antagonisms between wrinkle score and some production traits, primarily fleece weight and fibre diameter. Thus, simultaneous improvement in both flystrike resistance and production will be most efficient when index selection is used. Our results show that, depending on the level of emphasis placed on breech wrinkle in the index, reductions in breech wrinkle score of 0.4–0.9 units can be achieved over a 10-year period. As across-flock relationships are generally stronger than within-flock relationships, breeders will be able to take advantage of this additional variation, depending on the relative merit of their flocks. Therefore, ram breeders should combine within-flock selection with across-flock selection where possible. Sheep Genetics released early breech wrinkle Australian Sheep Breeding Values in September 2009 to assist Merino breeders in making faster progress towards reducing breech wrinkle by using flock selection.

scholarly journals High Heritabilities for Antibiotic Usage Show Potential to Breed for Disease Resistance in Finishing Pigs

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 829
Author(s):  
Wim Gorssen ◽  
Dominiek Maes ◽  
Roel Meyermans ◽  
Jürgen Depuydt ◽  
Steven Janssens ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Animal Health ◽  
Molecular Genetic ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Antibiotic Usage ◽  
Finishing Pigs ◽  
Production Traits ◽  
Parenteral Antibiotic ◽  
On Farm

The use of antimicrobials in animal production is under public debate, mainly due to the risk of transfer of resistance to pathogenic bacteria in humans. Therefore, measures have been taken during the last few decades to reduce antibiotic usage in animals, for instance, by national monitoring programmes and by improving animal health management. Although some initiatives exist in molecular genetic selection, quantitative genetic selection of animals towards decreased antibiotic usage is an underexplored area to reduce antibiotic usage. However, this strategy could yield cumulative effects. In this study, we derived new phenotypes from on-farm parenteral antibiotic records from commercially grown crossbred finishing pigs used in the progeny test of Piétrain terminal sires to investigate the heritability of antibiotics usage. Parenteral antibiotic records, production parameters and pedigree records of 2238 full-sib pens from two experimental farms in Belgium between 2014 and 2020 were analysed. Heritability estimates were moderate (18–44%) for phenotypes derived from all antibiotic treatments, and low (1–15%) for phenotypes derived from treatments against respiratory diseases only. Moreover, genetic correlations between these new phenotypes and mortality were low to moderate (0.08–0.60) and no strong adverse genetic correlations with production traits were found. The high heritabilities and favourable genetic correlations suggest these new phenotypes, derived from on-farm antibiotics records, to be promising for inclusion in future pig breeding programs to breed for a decrease in antibiotics usage.

scholarly journals Corrigendum to: Consequences of genetic selection for environmental impact traits on economically important traits in dairy cows

2018 ◽  
Vol 58 (10) ◽  
pp. 1966
Author(s):  
Purna Kandel ◽  
Sylvie Vanderick ◽  
Marie-Laure Vanrobays ◽  
Hélène Soyeurt ◽  
Nicolas Gengler
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Selection Response ◽  
Direct Selection ◽  
Correlated Response ◽  
Production Traits ◽  
Ch4 Emissions ◽  
Natural Logarithm

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits and the prediction of their selection response. In this study, test-day CH4 emissions were predicted from milk mid-infrared spectra of Holstein cows. Predicted CH4 emissions (PME) and log-transformed CH4 intensity (LMI) computed as the natural logarithm of PME divided by milk yield (MY). Genetic correlations of PME and LMI with traits used currently were approximated from correlations between estimated breeding values of sires. Values were for PME with MY 0.06, fat yield (FY) 0.09, protein yield (PY) 0.13, fertility 0.17; body condition score (BCS) –0.02; udder health (UDH) 0.22; and longevity 0.22. As expected by its definition, values were negative for LMI with production traits (MY –0.61; FY –0.15 and PY –0.40) and positive with fertility (0.36); BCS (0.20); UDH (0.08) and longevity (0.06). The genetic correlations of 33 type traits with PME ranged from –0.12 to 0.25 and for LMI ranged from –0.22 to 0.18. Without selecting PME and LMI (status quo) the relative genetic change through correlated responses of other traits were in PME by 2% and in LMI by –15%, but only due to the correlated response to MY. Results showed for PME that direct selection of this environmental trait would reduce milk carbon foot print but would also affect negatively fertility. Therefore, more profound changes in current indexes will be required than simply adding environmental traits as these traits also affect the expected progress of other traits.

Genetic analysis of docility score of Australian Angus and Limousin cattle

2018 ◽  
Vol 58 (2) ◽  
pp. 213 ◽  
Author(s):  
S. F. Walkom ◽  
M. G. Jeyaruban ◽  
B. Tier ◽  
D. J. Johnston
Keyword(s):  
Adverse Effect ◽  
Animal Model ◽  
Genetic Analysis ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Production Costs ◽  
Breeding Value ◽  
Maternal Behaviour ◽  
Production Traits ◽  
Subjective Score

The temperament of cattle is believed to affect the profitability of the herd through impacting production costs, meat quality, reproduction, maternal behaviour and the welfare of the animals and their handlers. As part of the national beef cattle genetic evaluation in Australia by BREEDPLAN, 50 935 Angus and 50 930 Limousin calves were scored by seedstock producers for temperament using docility score. Docility score is a subjective score of the animal’s response to being restrained and isolated within a crush, at weaning, and is scored on a scale from 1 to 5 with 1 representing the quiet and 5 the extremely nervous or anxious calves. Genetic parameters for docility score were estimated using a threshold animal model with four thresholds (five categories) from a Bayesian analysis carried out using Gibbs sampling in THRGIBBS1F90 with post-Gibbs analysis in POSTGIBBSF90. The heritability of docility score on the observed scale was 0.21 and 0.39 in Angus and Limousin, respectively. Since the release of the docility breeding value to the Australian Limousin population there has been a favourable trend within the national herd towards more docile cattle. Weak but favourable genetic correlations between docility score and the production traits indicates that docility score is largely independent of these traits and that selection to improve temperament can occur without having an adverse effect on growth, fat, muscle and reproduction.

Genetic parameter estimates for feeding pattern and production traits in pigs

1997 ◽  
Vol 1997 ◽  
pp. 31-31
Author(s):  
A.D. Hall ◽  
W.G. Hill ◽  
P.R. Bampton ◽  
A.J. Webb
Keyword(s):  
Feed Intake ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Feeding Pattern ◽  
Parameter Estimates ◽  
Group Housing ◽  
Production Traits ◽  
Production Environment ◽  
Feeding Patterns ◽  
Potential Benefits

Until recently, to enable accurate recording of feed intake, pigs were kept in individual pens. The advent of electronic feeders has allowed accurate records of feed intake and feeding patterns in group housing which is more similar to that found in the production environment. The objectives of this study were to estimate genetic parameters for these feeding pattern traits and their correlations with production traits to show potential benefits in selection.

The incorporation of fertility indices in genetic improvement programmes

2001 ◽  
Vol 26 (1) ◽  
pp. 237-249 ◽  
Author(s):  
J.E. Pryce ◽  
R.F. Veerkamp
Keyword(s):  
Genetic Variance ◽  
Selection Index ◽  
Genetic Correlations ◽  
Live Weight ◽  
Parameter Estimates ◽  
Phenotypic Variance ◽  
Production Traits ◽  
Genetic Progress ◽  
Detection Rates ◽  
Days Open

AbstractIn recent years there has been considerable genetic progress in milk production. Yet, increases in yield have been accompanied by an apparent lengthening of calving intervals, days open, days to first heat and a decline in conception rates, which appears to be both at the genetic and phenotypic level. Fertility has a high relative economic value compared to production traits such as protein, making it attractive to include in a breeding programme. To do this there needs to be genetic variance in fertility. Measures of fertility calculated from service dates have a small genetic compared to phenotypic variance, hence heritability estimates are small, typically less than 5%, although coefficients of genetic variance are comparable to those of production traits. Heritabilities of commencement of luteal activity determined using progesterone profiles are generally higher, and have been reported as being from 0.16 to 0.28, which could be because of a more precise quantification of genetic variance, as management influences such as delaying insemination and heat detection rates are excluded. However, it might not be the use of progesterone profiles alone, as days to first heat observed by farm staff has a heritability of 0.15. The most efficient way to breed for improved fertility is to construct a selection index using the genetic and phenotypic parameter estimates of all traits of interest in addition to their respective economic values. Index traits for fertility could include measures such as calving interval, days open, days to first service, or days to first heat but there may also be alternative measures. Examples include traits related to energy balance, such as live weight and condition score (change), both of which have higher heritabilities than fertility measures and have genetic correlations of sufficient magnitude to make genetic progress by using them feasible. To redress the balance between fertility and production, some countries already publish genetic evaluations of fertility including: Denmark, Finland, France, Germany, Israel, The Netherlands, Norway and Sweden.

Genetic variation in net feed efficiency in Hereford cattle and its association with other production traits

1999 ◽  
Vol 1999 ◽  
pp. 47-47
Author(s):  
R.M. Herd ◽  
S.C. Bishop
Keyword(s):  
Growth Rate ◽  
Genetic Variation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Genetic Correlations ◽  
Feed Consumption ◽  
Production Traits ◽  
Performance Measurements ◽  
Hereford Cattle ◽  
Rate Selection

Net feed efficiency refers to variation in feed consumption between animals net of requirements for maintenance and production, and may be measured as residual feed intake (RFI). Because RFI is independent of liveweight (LW) and growth rate, selection for improved net feed efficiency is likely to reduce feed intake with little change in growth. The purpose of this study was to establish whether there exists genetic variation in RFI in young British Hereford bulls, and to determine the phenotypic and genetic correlations of RFI with key production traits.The data consisted of performance measurements on 540 bull progeny of 154 British Hereford sires, collected over ten 200-day postweaning performance tests conducted between 1979 and 1988. The traits analysed were food intake (FI), 200 to 400-day daily gain (ADG), 400-day weight (W400), predicted carcass lean content (LEAN), lean growth rate (LGR), food conversion ratio (FI/ADG) and lean FCR (LFCR; FI/(ADG x LEAN), described by Bishop (1992).

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